Dec 24

Was Rudolph a Girl? (and other Christmas-related mini questions)

Christmas Day is almost upon us, so Extraordinary Animals will once again be asking a few quick questions about the natural world – with a Christmas twist, of course! That means mistletoe, robins and, of course, Santa’s reindeer…

Which Christmas plants are parasites?

When we think of parasites, we tend to think of tapeworms within our bodies, or wasps that lay eggs inside caterpillars, but many plants can also be parasitic. A plant from Western Australia, Nuytsia floribunda, known locally as the Christmas tree, steals water from the roots of nearby bushes and trees using its own roots. This isn’t the type of tree you would put up in your living room at Christmas, though – it’s only named the Christmas tree because it flowers in December.


But one parasitic plant that really is associated with Christmas is mistletoe. Mistletoe doesn’t even have its own roots, so it instead attaches itself to the branch of a tree. Although it can grow leaves and photosynthesise for itself, its lack of roots means that it must absorb water from the tree it is attached to, thereby reducing the tree’s own liquid.

The custom of kissing someone under the mistletoe probably originated in Scandinavia in the early 1800s. Mistletoe was often seen as a representation of divine male essence and thus romance, fertility and vitality, and is today commonly used as a Christmas decoration.

What is the most abundant animal on Christmas Island?

When Captain William Mynors of the Royal Mary sailed past an undiscovered island in the Indian Ocean on Christmas Day, 1643, he unimaginatively named it Christmas Island. The island is home to a few endemic species, the most famous – and most numerous – being the Christmas Island red crab. Although the ancestors of all crabs came from the sea, this particular species spends almost its entire life on land, primarily in burrows on the forest floor in the interior of the island.


Photo: John Tann

During the breeding season, the crabs leave their homes and begin a mass migration toward the sea. The huge size of their population soon becomes apparent, as over 40 million crabs march across the island. Nothing can halt their momentum, not even busy roads that have been built over their traditional migration routes. Tens of thousands of crabs fall afoul of human vehicles or predators but the onslaught continues, and after a week of travelling the survivors arrive at the beach and start mating.

At the turn of the tide in the last quarter of the moon, the females creep down to the very edge of the sea and release their eggs – up to 100,000 each. The eggs need to be deposited directly into the ocean if they are to hatch, but the adult crabs will drown if they are swept away by the waves. At the height of this spectacle, as millions of females rush to release their eggs in convulsive shakes of their bodies, the entire beach is transformed into a seething scarlet carpet of crabs.


Photo: Max Orchard, Parks Australia

Very few of the crab hatchlings will survive to adulthood. As they drift aimlessly in the ocean currents, most will be eaten by predators. Even those that survive cannot assume their final adult form unless they reach dry land, which the vast majority never do. In some years, the entire spawning is lost. But occasionally, about once every six years, fortunate currents take the young crabs back to Christmas Island. They march back up the beach and head inland to restock the forest.

Why are robins associated with Christmas?

The quintessential Christmas bird, if the media and Christmas cards are anything to go by, must surely be the robin. But where does its association with Christmas, and the winter season in general, come from? Well, according to legend, it was a robin who sang in Jesus’s ear to comfort him from his pain when he was dying on the cross. Back then, all robins were simply brown in colour, but the blood from Jesus’s wounds stained the bird’s breast red, and therefore all robins got the mark of Christ’s blood upon them.


Photo: F. C. Franklin

But the association with Christmas much more likely arose because postmen in Victorian Britain wore red uniforms and were nicknamed ‘Robins’ or ‘Redbreasts’ (red was considered a royal colour and was why British post boxes were standardised to be red). The Robin featured on the Christmas card was originally the postman delivering mail in the snow, but it eventually evolved to depict the Robins’ namesake, the robin bird.

Is Rudolph the Red-Nosed Reindeer a Girl?

Recently, it seems to have become a trend to assume that Rudolph the Red-Nosed Reindeer was actually a girl – even QI has stated this several times. Admittedly, there is some evidence to back this theory up. For instance, reindeer are unique among deer in that both male and female possess antlers. Whereas males lose their antlers at the start of winter, females keep them until they give birth in spring. Since Rudolph is seen with antlers around Christmas time, ‘he’ could very well be a female.


Photo: Per Harald Olsen

But there is an alternative theory. Rudolph (and the rest of Santa’s male reindeer) could simply be castrated, for castrated males have antler cycles very similar to those of females. Indeed, the majority of reindeer used to pull sleds in the real world are castrated males, so maybe Santa uses them as well.

As a side note, people have worked out that for Santa to deliver all his presents in one night, he would need to have over 214,000 reindeer pulling his sleigh, but they would be travelling so fast that they would instantly burn up like a meteorite. And that might ruin Christmas for a few children.

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